Electromagnetic sound-reproducing apparatus



Oct. 28, 1930. w. c. ANDERSON 1,779,722

ELECTRQMAGNETIC SOUNDREPRODUCING APPARATUS Fiied June 12, 1928 5 Sheets-Sheet 1 v, ATTORW Y Oct. 28, 19 0. w; c ANDERS N 1,779,722

ELECTROMAGNETIC SOUND REPRODUGING APPARATUS Filed June 12, 1928 S SheetS-Sheet 2 INVENTOR. %/ZZ2 Q/zzdamsozg I I .ATZORNEY Oct. 28, 1930-. w. c. ANDERSON 1,779,722

ELECTROMAGNETIC SOUND REPRODUCING APPARATUS Filed June 1 2, 1928 5 Sheets Sheet 5 "TIT-3.2

INVENTOR. I

ATTORNEY Oct. 28, 1930; w. c. ANDERSON 1,779,722

ELECTROMAGNETIC SOUND REPRODUCING APPARATUS Filed June 12, 1928 5 Sheets-Sheet 4 i I N V EN TOR. WZZZZGT 6'. flyuiemsan,

@ A TTORNEY Oct-#28, 930. w. c. ANDERSON 1,779,722

ELECTROMAGNETIC SOUND REPRODUCING APPARATUS Filed June 12, 1928 5 Sheets-Sheet 5 INVENTOR. I %ZZ2'2' Cflfldensan,

5, A TTORNEY UNITEDYSTATES,

Patented Oct. 28, 1930 PATENT OFFICE.

WA TER c. annnnson, on GLEN ROCK, NEW JERSEY, nssrenon'ro BRANDES LABORA- o TORIES, me, F NEWARK, NEWJERSEY, A CORPORATION on NEW JERSEY ELECTROMAGNETIC sounn-nnrnonuemenrrnnn'rus Application filed J1me 12,

. invention relates -broadly to electroti-cularly to asoundreproducer of magnetic sound reproducers and morepan the conical diaphragm type. 7 c 7 One of the objects of my invention is to provide a construction of electromagnetic sound reproducer. which is. capable of manufacture and production on a mass-production scale having a minimum number of parts which may be assembled with a minimum degreeof skill for efficient operation in the reproduction of sound over a broad .frequency'range.

"Another .object of-my invention is to provide a practical {construction of sou-nd reproducer wherein an electromagnetic operating. mechanism may-be suspended within a chassis and all parts of the electromagnetic sound re producer supported by? the chassis, thereby forming a compact assembly of the sound reproducer. y A further object of my invention is to pro vide a chassis construction for a loud speaker whereina conical shaped-diaphragm may be supported by a chassis ,inia position to be driven from the electromagnetic operating mechanism carried in "tlie'chas'sis for providng compact assembly of electromagnetic sound reproducer particularly adapted for mounting within a cabinet structure;

Still-another object f my invention is to provide a construction of electromagnetic sound reproducer,- wherein a pivoted armaturemember is assembled within an electromagnetic driving system an'd' b'etween pairs of inwardly directed pole faces with a bridging member extending over the electro- -magnetic operating mechanism and carrying means for transferring vibrations from the V pivoted armature to a conicalshapedsound reproducing diaphragm.

' Other an'd'further objects of my'invention reside inthe construction of parts'for'an elecparticularlyladapted for mounting within :a

structure.

1923. Serial No." 234,773. .7

diaphragm; Fig. 2 a side elevation ofthe assembled electromagneticsound reproducer; Fig. 3 1s a-lateral cross-sectional view of the electromagnetic sound reproducer illustrated in Fig. 2; Fig. 4 is alongitudinal.cross-sectional view taken through the electromagnetic sound reproducer; Fig. 5. is .a. .perspective view of the bridging member employed for the vvibration transfer. element between ing system.;an-d Fig. 8 is a lateral cross sectional view taken 'throughthe chassis illusr I :In myapplication Serial No. 179,026, filed v -March28,"1927, Ihav e shown a construction of pivoted armature electromagnetic sound reproducer over which the present construction of-is'ound reproducer 1S asubstantial' improvement. By my present design of sound reproducer, I provide a unitary means for mounting all ofthe parts of the sound rebe anchored to a' base structure and which-is cabinet. castichassis substantially in' the formof box-like frame is provided which gproducer by means of a chassis which may chassis terminates in a ring shaped portion providing a support for'apluralitfy of radial, arms which; carry a rim-structure from which the conical shaped s'oundreproducing diaphragm isflexibly suspended. 'The electro- -magnetic operating mechanism is mounted upon the chassis-anda. connectionextends from: a vibratory. armature member; to; the

apex of a conical :shaped sound reproducing --di aphragm,'which projects through the ring shaped extremity of --thechassisa The' elecby-afdevice from; which the vibration transfer memberis suspended Thejparts of the operating mechanism and the; sound reprowith-respect to the tromagnetic operating mechanism is bridged ,ducing diaphragm arecompactly assembled v chassis of the loud speaker r 1 V f I Referring to the drawings in more detail, reference character 1 designates a base on which a chassis 2 is mounted. The chassis includes a pair of side plate portions 3 and 5 a front plate portion 4 terminating in aring shaped portion 5. The front plate portion 4 is strengthened by means of a rib 40. The

side plates 30 terminate in supporting ledges 20 having intermediate cut away portions 20 The ring shapedterminus of the front plate 4 is provided with a hub portion 41 which has flattened areas16 at diametrically opposite points around the periphery thereof which-provide connection means for the m diating arms 8 of the frame for the conical shaped sound reproducing diaphragm. A pair of rim members-9 and 10 secured by means of rivets 42 are supported by means of l the arms 8. Rims 9 and 10 are substantially channel shaped, thus providing means for supporting the annular pad 11 which may be forced against the rear of'a panel which forms the front ofa cabinet structure. A

flexible annular membrane 43 is secured be- 5 tween the rim members 9 and 10 and connects to the peripheral edge of the cone shaped sound reproducing diaphragm 7. To provide suflicient damping of thesound reproducing diaphragm, I employ an annular "'3 strip 12 surrounding a portion of the dia 'phragmas set forthmore fully in copending application Serial No. 172,767 filed by Ralph Brown, March 4, 1927 The electromagnetic operating mechanism includesa' pair "35 of permanent" magnets shown at 15 which are secured on opposite sides of a pair of pole pieces 21 and 22 supported'by means of bolt members 17 on angle. members 16, which, are in turn supported .on the ledges '6 20 0f theside plates 3 and secured in posi- 'tion bymeans of screws 45 as shown. The pole pieces 21 and 22'which'are'dire'cted towardjeach other are cut away in the form of pockets 23 and 24 at their. adjacent'ends,

' thereby forming'sets of pole faces23 24 and 23 24 The pockets 23 and 24 'provide housings for bobbins 25 and26, each of which carry electromagnetic windings. The ends of the bobbins extend laterally in the 5 form of flat parallel plates indicated at 29 and 30', betweenthese end plates there is supported a resilient plate member 28 in which the arm'ature member 31 is. centrally positioned. the'armaturemember being free '5 to vibrate in a rocking movement in plate 28 under the influence of the variable magnetic I field from bobbins 25 and 26, The assembly "bf the electromagnetic windings is carried by the parallel extending bar members 33 6 which form an integral part of a single yoke "shaped casting represented at 32 for bridging ithe'pole members 21 and 22. The bridging member has the yoke portion thereof 32 ad- 7 jacent one end of the parallel extending bars 33 so that the assembly of the electromag' netic operating mechanism may be supported on plates 30 and 29 by means of screw members 46 which pass into screw threaded apertures in bars 33. The top of the yoke 32 is flattened as represented at 34 to provide a supportfor the vibration transfer member which depends downwardly from the fiattened portion 34. The vibration transfer member 35 has a connecting rod 47 extending from its lower extremity for the transfer of vibrations from armature .31 to the member 35 and then to the sound reproducing diaphragm 7 through the medium of link 36, bushing 37v and theapex piece 38. In order to improve the tone quality of the circuit, provision is made for the mounting of the frame of a choke coil as represented at 49on one of the side plates 3-by suitable securing means such. as screw devicesf50l A suitable 'terminalp'late 48 may be mounted on the 1 extremity of one of the side plates bridging the gap20 between the ledges 20. A suitable condenser may be mounted adjacent the choke coil and supported from thechassis with flexible connections brought out from the choke coil and condenser circuit and from the circuits of the electromagnetic windings for conveying the operating cur rents from the output system of an amplifier to the electromagnetic operating mechanism.

The loud speaker construction of my invention has been found to be extremely practical in its construction and successfulin its operation.

While I have described particular embodiments of'm'y invention, I desire that it be understood thatmodifications may be made and that no limitations are intended other than are imposed by the scope'of the appended claims; I

What I claim and desire to secure .by Letters Patent of the United'States is as follows "1. A loud speaker comprising a sound reproducing diaphragm, a pair of permanent magnets, pole pieces positioned therebetween and directed toward eachother, an armature located between said pole pieces, an electro-. magnetic system disposed between said pole pieces, a bridging member having a central portion :extending laterally of said pole and connecting means extending from said ring shaped member to said frame for maintaining said frame in predetermined relation to said chassis, and means connecting said diaphragm with said electromagnetic driving system.

- 3. In a loud speaker construction a chassis terminating in a substantially circular member adjacent one side thereof, an electromagnetic driving mechanism supported by said chassis, a frame for supporting a sound re producing diaphragm and radiating arm members extending from said frame and connected to said member for maintalmng a predetermined relation between said electromag-v netic driving mechanism and said sound re-. producing diaphragm.

4. In a loud speaker construction a chassis terminating at one side thereof in a ring shaped member, an electromagnetic driver supported on said chassis, a conical shaped sound reproducing diaphragm having the apex portion thereof projecting through said ring shaped member and connected to said electromagnetic driver, and means extend-.

ing from said ring shaped member to the outer periphery of said diaphragm for centering said diaphragm with respect to said ring shaped member. 7

5. A loud speaker comprising a chassis, a pair of angle members supported by' said chassis, an electromagneticoperating mechanism carried between said angle members, a

sound reproducing diaphragm, means sub- A stantially encircling said electromagnetic operating mechanism in a plane offsetfrom one side thereof for supporting said soundreproducing diaphragm from said chassis, and connecting means between said electromagnetic operating mechanism and said sound reproducing diaphragm.

6. A loud speaker comprising a chassis, an

electromagnetic operating mechanism carried by said chassis, a conlcal shaped sound reproducing diaphragm supported from said I chassis and connected to said electromagnetic operating mechanism, said chassis including a pair of vertically extending'side plate members terminating in parallel extending ledges on the top thereof, and an encircling portion through which the apex ofsaidconical shaped sound reproducing diaphragm extends for connection to said electromagnetic operating mechanism, 7 In aloud speaker construction a chassi for supporting the parts of-the loud speaker comprising'a pair of vertically extending side members terminating in' parallel extending- V ledges, a vertical plate member extending 4 above the parallel extending ledges of said chassis, a conical shaped sound reproducing diaphragm, a frame. supporting said dia phragm, connections between said frame and said chassis, an electromagnetic operating mechanism supported on the ledges of said chassis, said sound reproducing diaphragm having its apex extending through a portion of said'vertical plate member and connected to said electromagnetic operating mechanism.

8. In a loud speaker, a supporting chassis comprising a vertically extending frame, an

electromagnetic operating mechanism supported on theextremity of said frame, a conical shaped sound reproducing diaphragm, means supporting said conical shaped sound reproducing diaphragm comprising a rim, a

curved frame on said chassis located in a. plane offset from one side of said electromagnetic operating mechanism, and a plurality of arms extending between said rim and'said curved frame, said diaphragm having-its apex protruding' through an aperture in said curved frame and connected to said electromagnetic operating mechanism r i 9. A loud speaker comprising a frame structure, a pair of pole pieces supported by said frame structure and directed toward each other, a plurality of electromagnetic windings housed by said pole pieces with pole faces extending to positions" adjacent each other on opposite sides ofsaid electromagnetic windings, an armature member pivotally mounted within said electromagnetic windings, a conical'shaped sound reproducing diaphragm supported from said frame structure, means extending laterally of said pole pieces and connected at each end with said pole pieces, said means having a central oflset portion, a Vibration transfer member connected at one end with the central offset.

portion of said means and at the other end with said. armature member, and a connec:

phragm.

10. A a magnetic operating mechanism comprlsmg a pair of pole pieces directed toward each other, pockets formed in each of said pole faces, electromagnetic windings disposed in said pocket/s,'an armature member rockable within said electromagnetic windings, a yoke member laterally bridging said pole p1eces,,

loud speaker comprising an electrotion between said member and said dia- 

